Solid state memories (SSMs) provide an efficient mechanism for storing and transferring data in a wide variety of applications, such as hand-held portable electronic devices. Individual memory cells within such memories can be volatile or non-volatile, and can store data by the application of suitable write currents to the cells to store a sequence of bits. The stored bits can be subsequently read during a read access operation by applying suitable read currents and sensing voltage drops across the cells.
Resistive random access memory (RRAM) is a type of SSM cell that provides different programmed resistances in relation to the presence or absence of migrated ions in an intervening barrier layer between opposing electrode layers. Some types of RRAM memory cells are designed to undergo an initial RRAM cell formation processing operation during manufacturing prior to normal use of the cells to store data.
An RRAM cell formation operation may involve the application of a relatively large formation voltage across the cell for an extended period of time in order to prepare the RRAM cell for normal read and write operations. In some instances it has been found that large current spikes induced as a result of the formation voltage can damage the cells, leading to reduced manufacturing yields and longer term reliability issues.